1. Field of the Invention
The field of the invention generally relates to a high-stiffness, lightweight beam for use in manufacturing structures. More particularly, the invention relates to longitudinal structural elements for incorporation into photovoltaic panel assemblies.
2. General Background and State of the Art
Solar electric panels convert sunlight energy into electrical energy. As such, they can potentially compete with conventional methods of electricity generation, such as, for example, steam turbine generators fueled by coal, nuclear fuel, or natural gas.
In order for solar energy to compete on a large scale with conventional electricity generation, the cost of solar energy systems must be significantly reduced. Commercially-prevalent solar panels are manufactured almost entirely by automation, and their labor cost component has therefore already been minimized. The real cost-drivers of commercially-prevalent solar panels are the costs of the equipment, facilities, and energy for purifying and “growing” the monocrystalline silicon that constitutes the solar cells themselves. The solar energy industry is currently pursuing radical cost reduction by designing systems that minimize the use of the expensive purified silicon material.
One approach to minimizing silicon material use is to design the solar energy system using small solar cells spaced apart on a substrate, and using inexpensive converging lenses to focus large areas of sunlight onto those solar cells. This approach reduces the use of silicon, per kilowatt of power generating capacity, by a factor that approximates the optical concentration ratio of the lenses. In some cases the amount of silicon required may be reduced to 1/200th or less than that required by conventional flat plate solar panels. The configuration of such a lens-based concentrating photovoltaic system tends to resemble a “sandwich” of uniform thickness, with the lenses mounted on the top side of the sandwich, the solar cells spaced on substrates mounted on the bottom side of the sandwich, and the sunlight converging path traversing the empty space between the two. In order to keep the focused sunbeams centered onto the solar cells as the earth rotates below the sun, causing the sun to appear as though it is moving across the sky, the entire solar module structure must accurately track the sun, and the solar module structure must be significantly rigid such that its flexural “sag” does not significantly degrade the relative alignments of the lenses and solar cells.
What has been needed is a beam member used to form a structure for a pedestal-mounted solar panel system that is cost efficient, increases the ratio of flexural stiffness to material volume of the beam, includes a shape and size that facilitates attachment of components to the system, and has the ability to be fabricated from pre-galvanized or pre-coated sheet metal.